Hand pump for priming a fuel or filter system

ABSTRACT

A hand pump ( 16 ) includes a housing ( 22 ) having an inlet ( 18 ) and an outlet ( 26 ) and an actuating body ( 32 ) movably mounted in the housing axially and a membrane ( 46 ) with a flexible ring section ( 48 ) surrounding the stroke axis ( 34 ). During stroke movement, the actuating body ( 32 ) is pressed with the membrane ( 46 ) against the force of an elastic element ( 42 ) from a resting position (I) into the pump housing ( 22 ) and into an actuating position, and returned to the resting position (I) by the elastic element ( 72 ). Thus, the volume of a pump chamber ( 20 ) can be modified.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is US National Stage Entry of international patentapplication no. PCT/EP2010/062479, filed Aug. 26, 2010 designating theUnited States of America, the entire disclosure of which is incorporatedherein by reference. Priority is claimed based on German patentapplication no. 10 2009 048 211.3 filed on Oct. 5, 2009.

TECHNICAL FIELD

The invention concerns a hand pump for pumping fluids, in particularfuel, in particular of a motor vehicle, comprising a pump housing thathas an inlet and an outlet for the fluid and an actuating member that issupported therein so as to be axially moveable relative to a stroke axisas well as a membrane with a flexible ring section that surrounds thestroke axis, wherein the ring section is attached radially inwardly in afastening area of the actuating member and radially outwardly in aholding area of the pump housing, wherein the actuating member with themembrane is forced against the force of an elastic element from a restposition into an actuating position into the pump housing upon a strokemovement and by means of the elastic element is returned into the restposition and, in this way, the volume of the pump chamber can bechanged, wherein a stroke height of the actuating member is greater thana smallest radial spacing between the holding area and the fasteningarea during a stroke.

The invention concerns moreover a filter system for fluids, inparticular fuels, in particular of a motor vehicle, comprising a handpump for pumping the fluids, with a pump housing and an actuating memberthat is supported therein so as to be axially moveable relative to astroke axis as well as a membrane with a flexible ring section thatsurrounds the stroke axis, wherein the ring section is attached with aradially inwardly positioned side in a fastening area of the actuatingmember and with a radially outwardly positioned side in a holding areaof the pump housing, wherein the actuating member with the membrane isforced against the force of an elastic element from a first end positioninto a second end position into the pump housing upon a stroke movementand by means of the elastic element is returned into the first endposition and, in this way, the volume of a pump chamber can be changed,wherein a stroke height of the actuating member is greater than asmallest radial spacing between the holding area and the fastening areaduring a stroke.

PRIOR ART

Fuel supply systems for internal combustion engines are often providedwith hand pumps of the aforementioned kind that have the purpose offacilitating the starting operation when the tank has been run empty orafter exchange of a fuel filter. Such hand pumps are often combinedconstructively with a filter head to be connected to the fuel filter.

U.S. Pat. No. 6,019,890 A discloses a hand pump for conveying fuel in afuel supply system wherein the hand pump is constructively combined witha fuel filter. A housing bottom part of the fuel pump is formedintegrally with the connecting head for the fuel filter. On the housingbottom part a lid is attached by means of a securing ring. In a securingarea between the housing bottom part and the lid, the circumferentialwall of a membrane is clamped that extends substantially along the innerside of the lid. A radial inner area of the membrane is clamped in afastening area between the lower plate of a knob and a support plate.For pumping, the knob is pressed against a spring pretension and reducesin this way the volume of a pump chamber. In this connection, thefastening area remains on one side of the holding area so that thestroke height is correspondingly limited and a large portion of thepossible stroke volume remains unused.

The invention has the object to provide a hand pump and a filter systemwith a hand pump of the aforementioned kind in such a way that a strokevolume as large as possible is realized with a constructive space assmall as possible.

SUMMARY OF THE INVENTION

This object is solved according to the invention in that the holdingarea of pump housing, axially viewed relative to the stroke axis, ispositioned between the position of the fastening area in the restposition and the position of the fastening area in the actuatingposition.

According to the invention, the fastening area of the actuating memberis thus moved past the holding area when a stroke is performed. In thisway, the freedom of movement of the membrane is optimally utilized and,in this way, the stroke volume that is achievable for the predeterminedconstructive space is maximized. Since the stroke height is greater thanthe smallest possible spacing between the holding area and the fasteningarea, the gap between a radial inner circumferential side of the pumphousing and a radial outer circumferential side of the actuating memberis minimized. Preferably, the width of the gap is less than 5 mm. Themembrane is optimally supported with respect to the changing pressureloads by the fastening area with a diameter that is as large aspossible; this has a positive effect on the stroke volume. Upon intakeof the fluid, in the pump chamber underpressure exists relative to apressure in the fluid supply conduit. Upon pumping fluid out of the pumpchamber, an overpressure exists relative to a pressure in a fluiddischarge line.

In an advantageous embodiment, the holding area of the pump housing canbe positioned centrally between the position of the fastening area inthe rest position and the position of the fastening area in theactuating position of the actuating member. In this way, the axialdeflection of the actuating member is identical on both sides of theholding area so that the stroke height can be maximized and theavailable constructive space is utilized optimally.

Advantageously, the ring section of the membrane can be curved andevertable; in particular, the membrane can be a rolling membrane. Inthis way it is possible that the ring section, when passing the holdingarea, can be everted with minimal force expenditure in the gap betweenthe fastening area in the holding area. A rolling membrane can be simplyeverted even for minimal gap widths.

The membrane can advantageously be comprised of an elastomer. Elastomersare flexible, robust, and moreover can be simply configured to havecomplex shapes.

Advantageously, the membrane can have a circumferentially extendingsealing bead that is clamped between a lid and a housing bottom part ofthe pump housing. In this way, an excellent sealing action between themembrane and the pump housing is achieved so that the escape of fluidthe holding area is prevented.

According to a further advantageous embodiment, the actuating member canhave an exterior cap on which or in which a support cap is arranged andthe membrane can be clamped between the exterior cap and the supportcap. In this connection, the membrane can be clamped flat and stablybetween the exterior cap and the support cap in the area of its center.A separate seal in the fastening area is thus not required.

However, there is also the possibility that the membrane is embodied asa ring element and only a radial inner area of the ring element isclamped seal-tightly between the knob and the support cap. The membraneis optimized in this way with respect to material usage.

Alternatively, advantageously the actuating member can have a knob andthe membrane can be integrally injection-molded onto the knob and can beembodied as a ring element. A ring element is optimized relative tomaterial usage. The hand pump according to the invention is comprised inthis way of fewer individual parts and can therefore be mounted moreeasily.

Advantageously, the hand pump can be integrated in a filter system forfluids, in particular a filter head. In filter systems, it isparticularly advantageous when the employed components require as littleas possible mounting space. In this connection, the hand pump accordingto the invention with an optimal ratio between stroke volume andconstructive space is particularly advantageous.

The technical object is solved according to the invention furthermore inthat for the hand pump of the filter system the holding area of the pumphousing, axially viewed relative to the stroke axis, is located betweenthe position of the fastening area in the rest position and the positionof the fastening area in the actuating position. The aforementionedadvantages of the hand pump according to the invention apply likewise tothe filter system according to the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, features and details of the invention result fromthe following description in which an embodiment of the invention willbe explained in more detail with the aid of the drawing. A person ofskill in the art will consider features disclosed in combination in thedrawing, the description and the claims also individually and combinethem to expedient further combinations. It is shown in:

FIG. 1 schematically a section of a hand pump integrated into a filterhead of a fuel filter system;

FIG. 2 schematically a section of the hand pump of FIG. 1 duringactuation;

FIG. 3 schematically a different section of the hand pump of FIG. 1.

In the Figures, same components are provided with the same referencecharacters.

EMBODIMENT(S) OF THE INVENTION

In FIG. 1, a detail of a fuel filter system 10 of an internal combustionengine of a motor vehicle is illustrated. The fuel filter system 10comprises a filter head 12 on which an exchangeable filter 14, of nointerest in this context, is mounted.

A hand pump 16 is integrated into the filter head 12. The hand pump 16serves for manually sucking in fuel from a tank, for example, afterexchange of the exchangeable filter 14 or before restarting the internalcombustion engine when the tank has run empty.

In the filter head 12, an intake line 18 of the hand pump 16 isarranged. The intake line 18 is visible in the section view of FIG. 3.The intake line 18 is connected with a fuel supply line, coming from thetank and not illustrated in the Figures, and opens into a pump chamber20 of a pump housing 22 of the hand pump 16. In the intake line 18 aninlet check valve 24 is arranged that opens for sucking in fuel into thepump chamber 20.

A pressure line 26 of the hand pump 16 that is shown in FIGS. 1 and 2connects the pump chamber 20 with an inlet 28 of the exchangeable filter14. In the pressure line 26 an outlet check valve 30 is arranged whichopens for pumping fuel from the pump chamber 20 into the exchangeablefilter 14.

In the pump housing 22 a knob 32, identified as a whole by referencecharacter 32, is supported such that it is axially movable relative tothe stroke axis 34. The knob 32 is comprised of an exterior cap 36 and asupport cap 38.

The exterior cap 36 as a whole is approximately cup-shaped. On the freeend face of the exterior cap 36 a radial flange 40 is integrally formed.The support cap 38 is also approximately cup-shaped. It has at its freeend face a radial counter flange 42 whose radial outer rim is bent awayat a right angle from the bottom 44 of the support cap 38. The supportcap 38 is inserted into the exterior cap 36 wherein an approximatelycup-shaped membrane 46 of rubber that is of a stepped configuration atits circumferential side is clamped between the support cap 38 and theexterior cap 36.

A curved ring section 48 of the membrane 46 surrounds a fastening area50 of the knob 32 provided for the membrane 46 between the flange 40 andthe counter flange 42.

The ring section 48 has at the radial outer rim of the membrane 46 acircumferentially extending sealing bead 52. The sealing bead 52 isclamped in a holding area 54 between a lid 56 and an upper edge of ahousing bottom part 58 of the pump housing 22 and, in this connection,assumes at the same time a sealing function. The pump housing 22 issealed-tightly closed by crimping of the lid 56 on the rim.

The knob 32 that is provided with the membrane 46 projects through anopening 60 in the lid 56 outwardly wherein the radial flange 40 isresting at the inner side of the lid 56. The ring section 48 of themembrane 46 extends from the holding area 54 to the fastening area 50and is resting on the lid 56 in the rest position I of the knob 32 shownin FIGS. 1 and 3.

The cylinder section 62 extends away from the inner side of the bottom44 of the support cap 38 and is concentric to the stroke axis 34. Theaxial extension of the cylinder section 62 corresponds approximately tothe axial extension of the support cap 38.

The housing bottom part 50 comprises a cylindrical wall section 64having at its lower end a bottom 66. The bottom 66, the cylindrical wallsection 64, the membrane 46, and the knob 32 delimit the pump chamber 20whose volume is changeable by pressing down the knob 32 and thecorresponding movement of the membrane 46.

On the bottom 66, in concentric alignment to the cylinder section 62 ofthe support cap 38, two guide elements 68 are provided. The cylindersection 62 is located in a cylindrical interior that is delimited by theguide elements 68. The guide elements 68 are separated from each otheracross their entire length in the direction of the stroke axis 34 by twopassage slots 70 that are aligned in the FIGS. 1 and 2. By means of thepassage slots 70 fuel can pass from the area of the pump chamber 20surrounded by the guide elements 68 into the interior.

The guide elements 68 and the cylinder section 62 are surrounded by aspiral pressure spring 72. The spiral pressure spring 72 is supportedwith one end on the inner side of the bottom 66 of the housing bottompart 58 and with the other end on the inner side of the bottom 44 of thesupport cap 38.

For pumping fuel, the knob 32 with the membrane 46 is pressed againstthe force of the spiral pressure spring 72 into the pump chamber 20 fromthe rest position I into an actuating position II that is shown in FIG.2. In FIG. 1, the position of the fastening area 50 in the rest positionI is shown as a straight dashed line 73 and the actuating position II isindicated by a straight dashed line 75. The holding area 54 of the pumphousing 22 is positioned, viewed axially relative to the stroke axis 34,centrally between the position 73 of the fastening area 50 in the restposition I and the position 75 of the fastening area 50 in the actuatingposition II of the knob 32. In this way, the flexibility of the membrane46 is completely utilized and a greatest possible stroke height,indicated in FIG. 1 by double arrow 77, is achieved so that thereby agreatest possible stroke volume is achieved. The stroke height 77 of theknob 32 is greater than the smallest possible spacing between theholding area 54 and the fastening area 50 during a stroke. The widththat is indicated in FIG. 1 by the double arrow 74 of the gap 74 thatremains between the holding area 54 and the fastening area 50 ispreferably less than 5 mm.

Upon suppression of the knob 32, the ring section 48 of the membrane 46that is embodied as a rolling membrane is everted by means of a rollingshape change. The volume of the pump chamber 20 is reduced and thepressure in the pump chamber 20 increases. This pressure increase causesopening of the outlet check valve 30 so that fuel from the pump chamber20 is pumped through the pressure line 26.

After termination of the downward stroke of the knob 32, the forceloading by the hand of the operating person ends also. As a result ofthe restoring force, the spiral pressure spring 72 pushes the knob 32out of the pump chamber 20 until the radial flange 40 rests on the lid56. In this way, the ring section 48 of the membrane 46 is everted intoits original shape. The volume of the pump chamber 20 is increased andunderpressure is produced. The underpressure effects opening of theinlet check valve 24 so that fuel flows through the intake line 18 intothe pump chamber 20.

In the above described embodiment of a fuel filter system 10 and a handpump 16 the following modifications are possible inter alia.

The fuel filter system 10, in particular the hand pump 16, is notlimited to use in internal combustion engines in the automotive field.Instead, it can be used also in other internal combustion engines, forexample, industrial motors. The fuel filter system 10 and the hand pump16 can also be used in other technical fields, for example, in watertechnology for filtering or for sucking in water.

Instead of being integrated into the filter head 12, the hand pump 16can also be configured as a separate functional component. The hand pump16 can also be arranged at a different location in the fuel filtersystem 10.

Instead of being arranged centrally between the respective position 73or 75 of the fastening area 50 in the rest position I and the actuatingposition II, the holding area 54 of the pump housing 22, can also bepositioned closer to one of the positions 73 or 75.

The membrane 46, instead of being made of rubber, can also be made ofdifferent types of flexible material, in particular a different kind ofelastomer.

The support cap 38, instead of being inserted into the exterior cap 46,can also be pushed onto it.

The membrane 46, instead of being clamped between exterior cap 36 andsupport cap 38, can also be injection-molded onto an appropriate knoband can be embodied as a ring element.

Instead of the knob 32 with exterior cap 36 and support cap 38, adifferent knob, in particular a monolithic one, can be provided.

Instead of the spiral pressure spring 72 also a different kind of springor a different kind of elastic element can be provided.

The invention claimed is:
 1. A hand pump for pumping fluid of a motorvehicle, comprising: a pump housing, including a fluid inlet; a fluidoutlet; an actuating member arranged within said pump housing andsupported therein so as to be axially moveable relative to a strokeaxis; a membrane with a flexible ring section surrounding the strokeaxis, that is fastened radially inwardly in a fastening area of theactuating member and radially outwardly in a holding area of the pumphousing; wherein the actuating member with the membrane upon a strokemovement against the force of an elastic element is pressed from a restposition (I) into an actuating position (II) into the pump housing andby means of the elastic element is returned into the rest position (I)and in this way the volume of a pump chamber can be changed, wherein astroke height of the actuating member is greater than a smallest radialspacing between the holding area and the fastening area upon a strokemovement, wherein the holding area of the pump housing is positionedaxially between the fastening area rest position in the rest position(I) and the fastening area actuating position in the actuating position(II); wherein the actuating member has an exterior cap on or in which asupport cap is arranged and the membrane is clamped between the exteriorcap and the support cap; a first axially extending cylindrical guideelement formed on an interior surface of a housing bottom part at thebottom of pump chamber and extending axially towards the support cap,the first cylindrical guide element having an axially extending openinterior connected to the fluid outlet; wherein the first axiallyextending cylindrical guide element includes fluid passage slotsextending radially through the wall of the first cylindrical guideelement from the axially extending open interior into the pump chamber,the fluid passage slots passing fuel through the first cylindrical guideelement from the pump chamber to the axially extending open interior andon to the fluid outlet; wherein the support cap includes a secondaxially extending cylindrical guide element, the second axiallyextending cylindrical guide element sliding axially in the first axiallyextending cylindrical guide element as the actuating member moves fromthe rest position (I) to the actuating position (II).
 2. The hand pumpaccording to claim 1, wherein the ring section of the membrane is curvedand can be everted, wherein the membrane is a rolling membrane.
 3. Thehand pump according to claim 1, wherein the membrane is comprised of anelastomer.
 4. The hand pump according to claim 1, wherein the membranehas a circumferentially extending sealing bead that is clamped between alid and a housing bottom part of the pump housing.
 5. The hand pumpaccording to claim 1, wherein the actuating member comprises a knob andthe membrane is injection-molded onto the knob and is embodied as a ringelement.
 6. The hand pump according to claim 1, wherein the hand pump isintegrated into a filter head of a filter system.
 7. A filter system forfluids of a motor vehicle, comprising a hand pump according to claim 1.8. The hand pump according to claim 1, wherein the holding area of thepump housing is centrally positioned between the position of thefastening area in the rest position (I) and the position of thefastening area in the actuating position (II) of the actuating member.9. The hand pump according to claim 8, wherein the ring section of themembrane is curved and can be everted, wherein the membrane is a rollingmembrane, wherein the membrane is comprised of an elastomer, wherein themembrane has a circumferentially extending sealing bead that is clampedbetween a lid and a housing bottom part of the pump housing, wherein theactuating member has an exterior cap on or in which a support cap isarranged and the membrane is clamped between the exterior cap and thesupport cap, and wherein the actuating member comprises a knob and themembrane is injection-molded onto the knob and is embodied as a ringelement.
 10. The hand pump according to claim 9, wherein the hand pumpis integrated into a filter head of a filter system.